The purpose of this project is to analyze some of the factors involved in the regulation of collagen biosynthesis. The first factor analyzed was the mRNA molecule that contains the information for this protein. We have isolated and characterized the collagen mRNA for type I and type II collagens, and obtained information about its structure, composition, size and synthesis. The second analysis was related to factors involved in the translation of the mRNA into collagen; secondary structure, presence of specific tRNA's and translational control RNA's seem to play an important role in collagen mRNA translation. The third analysis is the detection of qualitative and quantitative changes of mRNA and DNA related to changes of collagen synthesis. This information will be obtained with the use of complementary DNA which has been synthesized with the use of reverse transcriptase and collagen mRNA as template. BIBLIOGRAPHIC REFERENCES: Lee-Own, V., Zeichner, M., Benveniste, K., Denny, P., Paglia, L. and Slavkin, H.C.: Cell-free synthesis of messenger RNAs of embryonic tooth organs: Synthesis of the major extracellular matrix proteins. Biochem. Biophys. Res. Commun. 74: 849-856, 1977. Zeichner, M. and Stern, R.: Resolution of ribonucleic acids by sepharose 4B column chromatography. Biochemistry 16: 1378-1382, 1977.